geiger

Geiger is a German surname that is most closely associated with the detecting of ionizing radiation, particularly through the Geiger counter and the Geiger-Müller tube. The Geiger counter, also called a Geiger-Müller counter, is a portable instrument used to measure radiation levels by counting electrical pulses generated when radiation ionizes gas inside a tube.

The detector’s core element, the Geiger-Müller tube, was developed by Hans Geiger and Walther Müller in 1928. It consists of a gas-filled tube with a central anode wire surrounded by a cathode. When ionizing radiation enters the tube, it ionizes the gas, and the resulting free electrons are accelerated toward the anode. This creates a cascade of ionization, producing a characteristic pulse that is counted by the instrument. Each pulse is typically interpreted as one radioactive event, and the instrument commonly reports counts per minute or per second.

Geiger counters are valued for their simplicity and speed in detecting the presence of radiation and gauging contamination, but they have limitations. They do not provide information about the energy or type of the radiation, and the tubes exhibit dead time after pulses that can undercount at high radiation levels. Modern radiation detection systems may supplement Geiger-Müller tubes with additional sensors to provide more detailed spectra or energy discrimination.

Beyond the instrument, Geiger is also a surname borne by various individuals in science and other fields.